In order to suppress reflection of light or increase transmittance of the light, a reflection reducing coating is ordinarily formed on a surface of a lens, such as a spectacle lens. There is a problem in that, at the time of use, a stain derived from adherence of, for example, dirt from a hand, a fingerprint, perspiration, or cosmetic is conspicuous and it is hard to remove the stain. In coping with this problem, in order to prevent the stain from adhering or to facilitate removal of the stain whenever adhered, an antifouling layer has further been provided on a surface of the reflection reducing coating.
With regard to a surface treating agent for providing the antifouling layer on the spectacle lens, a fluorine-containing silane compound which is described in JP-A No. 9-258003 to form the antifouling layer is favorable in terms of the antifouling property. Further, the effect thereof lasts long.
However, the lens which has been subjected to the surface treatment with the fluorine-containing silane compound as described in the above publication has an extremely small friction coefficient compared to that obtained by using a conventional surface treating agent. Therefore, the surface of the lens has such a characteristic as being too slippery. Due to this characteristic, a problem as described below occurs when the lens is subjected to edging. At a retail shop of spectacles, grinding a round spectacle lens to be in a shape in which the lens can be inserted in a spectacle frame, namely, so-called edging has been performed.
In the edging, first, a machining center of the spectacle lens is sucked and held by chucks of an edge-machining apparatus. In another case, the machining center of the spectacle lens is clamped while being applied with pressure from both sides of the lens. In a manner as described above, an edge of the spectacle lens is ground by a grinding stone while the spectacle lens is held by a frictional force. Since the surface of the lens held by the chucks has good slipperiness, when the lens is ground by a grinding stone, the lens slips out of position, due to a grinding pressure of the grinding stone against the chucks, namely, a so-called axial misalignment occurs. This causes a problem in that precise edging can not be performed.
Under these circumstances, the present invention has been achieved and has an object to provide a technique capable of allowing edging a lens on which an antifouling layer has been formed by using a fluorine-containing silane compound excellent in an antifouling effect.